Nano silver in protease treatment creates anti-friction, anti-static and antibacterial fabric
This study was performed by analyzing the effect of the surface treatment on wool using different percentages of protease (3%, 6% and 9%) with the incorporation of particles. Nano silver and according to pH changes (i.e., pH = 4 and pH = 7). The comparison of fiber surface morphology and FTIR analysis were performed to characterize the nano coating. The results showed that the antistatic and antibacterial effects on the samples treated at 3% protease and 6% protease were better than those treated at 9% protease. Correspondingly, samples treated at pH 4 had better antistatic and antibacterial properties than those treated at pH 7. Sulfur compounds played an important role in the interaction and adsorption. absorption of nano silver.
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INTRODUCTION
Although there are many types of synthetic fibers available today, natural fibers are still in high demand and preferred for use. Among other natural fibers, wool is also being chosen by most consumers as one of the important natural fibers. The livestock industry is not only established for meat and dairy, but they also provide wool or hair and thus positively affect the income of any country or state [ 1 ]. Regardless of the high market demand, wool yarn is not used as the most premium yarn due to its scarcity [ 2]. Primary wool fibers have more or less major shortcomings, i.e. the natural hydrophobicity of the outer surface due to the fatty acid layer, the surface roughness due to the structure of the cuticle, and is a good medium for growth and propagation. transmission of bacteria under suitable temperature and humidity. For the previous two methods, several techniques have been applied to decompose the fat surface layer [ 3 – 5 ] and/or coat or fabricate hydrophilic materials on the fatty acid layer on the wool fiber surface [ 3 – 5 ] [3 – 5 ] 6 – 8 ]. However, such treatments often cause some loss of mechanical properties and/or affect its natural feel and comfort.
The natural hydrophobicity of wool fibers causes an accumulation of electrical charges on the fiber surface. Antistatic treatment for wool textiles reduces electrical resistivity and facilitates charge dissipation on the fiber and thus reduces high potential discharge. Furthermore, by reducing the surface resistivity of woolen textiles, better soil-releasing, electrical and electromagnetic conductivity and heat shielding properties can also be achieved. Ki and associates. [ 9] maintained that the antistatic efficacy of finished wool fabrics with AgNPs on their surface increased slightly up to 50 ppm, after which it was found to decrease with the addition of AgNPs. Recently, a new method for the production of antistatic wool textiles by in situ synthesis of polypyrrole (PPy) and its treatments on the surface of wool textiles has been investigated [ 10 ]. Furthermore, Wang et al. [ 11 ] The pre-treated polyester fabric was then coated with single-walled carbon nanotubes (SWCNT) by coating-drying-curing under different plasma conditions, and it was found that suitable conditions should be used to optimizes the antistatic properties of polyester fabrics.
Not only on wool, but also on other textile media, some research has been done to make the yarn antibacterial. Dubas et al. [ 12 ] immobilize antibacterial silver nanoparticles (AgNPs) on nylon and silk fibers by sequentially dipping in dilute solutions of AgNPs coated with poly(methacrylic acid) and poly(diallyl dimethyl ammonium chloride) using method layer by layer deposition method. They claim an 80% reduction in bacteria for silk and 50% for nylon through the formation of a colored thin film. Khalil-Abad and Yazdanshenas [ 13 ] produced silver particles on cotton fibers by treatment with aqueous KOH and AgNO 3, followed by surface hydrophobation. Improved cotton fabrics are capable of killing both Gram-negative and Gram-positive bacteria on the fabric surface.
Yu et al. [ 14 ] synthesized silver nanoparticles (AgNPs) using natural Dolcetto grape leaves and fabricated them with alginate fibers by wet spinning and confirmed the antibacterial properties of alginate fibers against both Gram-positive pathogenic bacteria and Gram negative. Xue et al. [ 15 ] produces AgNPs on cotton fibers by in situ reduction of [Ag(NH 3 ) 2 ] + with glucose, then the treated textile is modified with alkylsilane with a long chain and high antibacterial activity than for Escherichia coli . Liu et al. [ 16] synthesized silver nanoparticles using solar irradiation and Nageia Nagi extract according to green chemistry and sustainability approaches and evaluated their antibacterial activity. Furthermore, the synthesis of AgNPs is being reported using variant natural leaves, such as bamboo [ 17 ], Chinese Holly [ 18 ], Gui Hua ( Osmanthus Fragrans ) [ 19 ], etc.
Nanoparticles provide multifunctionality to textiles being maintained after repeated washing [ 20 – 22 ]. Nanoparticles are being used for many different applications; besides their many benefits, there are a number of shortcomings and health problems associated with nanoparticles, as recently reviewed and reported [ 23 ]. However, silver has been reported to be one of the safe and non-toxic antibacterial agents for the human body that can kill harmful microorganisms [ 24]. The aim of this paper is to present the antibacterial, anti-worm and electrical properties of wool textiles by applying nano-glue. Here, we analyzed commercially available silver nanoparticles (AgNPs) for their predominant antibacterial and antistatic properties. Wool fabrics are pre-treated with a protease enzyme to make the wool surface receptive to nano silver.
Experiment
Material
Analytical grade enzyme Savinase 16L was purchased from Novozymes Biopharmaceuticals, Ltd, China. Silver beads (Ag + ) commercial grade (AGS-2YR-001) were supplied by Shanghai Nanotechnology Co., Ltd., China. Analytical grade hydrogen peroxide (H 2 O 2 ) and sodium carbonate (Na 2 CO 3 ) were purchased from China Medical Group Chemical Reagent Co., Ltd., China. Analytical grade sodium sulfite (NaHSO 4 ), sodium pyrophosphate (Na 4 P 2 O 7 ) and acetic acid (C 2 H 4 O 2) were purchased from Chemical Industry Corporation Limited, China. Country. Analytical grade sodium chloride (NaCl) was purchased from Hangzhou Gao Jing Fine Chemical Industry Co., Ltd., China. Peptone, yeast powder and jelly powder were supplied by Base Bio-Tech Co., Ltd., Hangzhou, China. Gram-negative bacteria Klebsiella pneumoniae ( K. pneumoniae ; ATCC 4352) and Gram-positive bacteria Staphylococcus aureus ( S. aureus ; ATCC 6538) were obtained from University of Life Sciences, Donghua University, China. Tween 20 is provided by Hainan Zhongxin Chemical Co., Ltd. Shanghai, China.
Fabric or wool samples were placed at standard temperature (i.e. 20 ± 2°C) and humidity (i.e. 65 ± 2%) of the environment before all experiments for 24 h to equilibrate to moisture. All samples were kept in a dry bag. All yarn samples had a unit mass of 15 g. The fabric samples were cut according to the test requirements. Alcohol ratio 1:30 was used in the experiment.
Coating H2O2 / Protease with nano silver
Tỷ lệ enzyme protease là khác nhau (ví dụ: 3%, 6% và 9%) trong xử lý bề mặt trước khi kết hợp các hạt nano bạc, và giá trị pH thay đổi ở giai đoạn kết hợp bạc; pH 4 và pH 7 đã được sử dụng. Thí nghiệm được tiến hành như minh họa trong Hình 1 .
Properties of nano silver coating
The surface morphology of fibers after protease treatment and silver nanoparticles was determined using a Scanning Electron Microscope (TM3000) with a magnification range of 20–30000X from Hitachi, Japan. SEM microscopy images taken at 2000X magnification are presented.
The protease-treated wool samples and nano silver were examined by infrared spectroscopy using the Thermo Fisher Nicolet 6700 Fourier Transform Infrared Spectrometer of the USA. The spectrum ranges from 4000 cm −1 to 400 cm −1 . The change of functional groups in the fibers before and after wool treatment was analyzed by the change of peaks and depressions in the spectrum.
Characterization of electrical properties
The fiber specific resistance of antistatic treated fibers was determined using a fiber specific resistance meter (XR-1A) from Changzhou Textile Instrument Ltd., China, with a resistance of 10 6 –10 13 Ω. The mean volumetric resistivity (Ω cm) of a 15 g, 10-foot sample, was measured. The testing of the samples was carried out at standard conditions of 20±2°C and 65±3% relative humidity.
Fabric half-life and static voltage were measured with a textile induced (fabric-induced) electrostatic tester (YG401) 10 kV 100000 s from Ningbo Textile Factory, China, according to Chinese standard FZ/ T01042-1996 “Determination of electrostatic half-life of electrostatic properties of textiles. “ Test conditions used are temperature of 20 °C and relative humidity, 30% -40%.
Characteristics of washing fastness
The washing fastness of nano-silver coated wool fibers is determined by complying with GB/T 3921.3-1997 Textiles – tests for color fastness – color fastness to washing. Nano-coated wool fibers were washed at 60°C in a washing solution prepared by 2 g/L Tween 20 (non-ionic detergent) for 5 min under gentle washing machine agitation. Then, rinse the wool fibers in cold water and then dry at 80°C. Nano-coated wool fibers are washed 20 times. The washing fastness of AgNPs on nano-coated wool fibers was evaluated by comparing the electrical properties of AgNPs before and after washing.
Properties of antibacterial properties
The antibacterial performance of wool samples was quantitatively evaluated against Gram-negative bacteria Klebsiella pneumoniae ( K. pneumoniae ; ATCC 4352) and Gram-positive bacteria Staphylococcus aureus ( S. aureus ; ATCC 6538) according to the AATCC test method. 100-1999. Both K. pneumoniae and S aureus were cultured on agar. Agar was prepared according to the method described in our previous paper [ 22 ]. Wool samples were placed on agar plates containing the bacteria, inoculated with S. aureus and K. pneumoniae. Wool samples were wetted with inoculum using ∼0.5% Tween 20, a commercial nonionic agent. The antibacterial performance of the wool samples was calculated after 24 h from exposure to the reduced percentage of bacteria (R%); Mathematically, it can be expressed by the following equation: where is the percentage reduction of bacteria, is the number of bacterial colonies formed by untreated wool, and is the number of bacterial colonies formed by treated wool.
R% = (A-B)/A*100%
Characteristic of fiber friction
The friction property of single yarn was tested using a yarn coefficient of friction meter (XCF-1A) with an accuracy of ±1 from Shanghai Institute, China. The static and kinetic coefficients of friction for each fiber were recorded at standard test conditions (i.e. 20 °C and 60% RH). Statistical data of kinematic coefficient of friction were collected and used in this study.
Results and Discussion
Effect on surface morphology of wool fibers
Surface morphology and effect of treatment on wool fibers were observed by scanning electron microscope (SEM) at 2000X (30 μ m) magnification. Microscopic images of the untreated samples are presented in Fig. From the microscopic image, it can be observed that the untreated surface of the wool fibers is covered with layers of scales that are arranged and intact like a tile. The edges of the scales are prominent.
Figure 2(a) shows unprocessed yarn. Figure 2(b) – 2(d) is wool treated with different protease ratios combined with the same 8% silver nanoparticles, all at pH 4. Figure 2(e) shows wool fibers treated with 6% protease and 8% silver nanoparticles at pH 7. After protease treatment/treatment, it can be seen that the scale structure changes according to the ratio of protease used, where the convexity and finish The capacitor of the scale is reduced. as protease used decreases and they become less deep. The disruption of flakes was increased although the scales were not completely stripped but deeper on the fibrous scales of the 9% protease treated sample. Its scab is attenuated and thinning of the fibers is visible. It can be seen that, after coating with antistatic agent, a continuous water-absorbing film will form on the scales, making the scale lines blurred and the whole body smooth, only the local scales are not completely covered. The fibers were treated at a higher pH (ie, 7) to expose the particles deposited on the fiber surface, and the flakes were further damaged. Therefore, raising the pH can affect the fiber surface properties. Furthermore, it can also be clearly seen that the higher the amount of silver absorbed at a lower pH, the higher it is.
Wool fibers at a pH higher than the isoelectric point have a negative surface charge. This charge will act as an initial limiting agent to absorb the anions. At lower pH, a significant proportion of the internal amine groups are protonated, causing neutralization of this surface charge and the absorption of higher amounts of AgNPs. It is clear that the increased temperature leads to a higher silver load on the fabric due to the increased kinetic energy. Under alkaline conditions, silver ions seem to catalyze the breakdown of cysteine, followed by the release of H 2 S and thus the formation of additional thiol groups, which are subsequently converted to mercaptides.
Analysis of the infrared spectrum of wool fibers after treatment
Fourier transform infrared spectroscopy was used to analyze wool fibers before and after processing, in order to investigate changes in fiber structure. The results are shown in Figure 3 . Band frequencies 1071 cm −1 and 1040 cm −1 were assigned to cysteic acid -SO 3 – and cysteine monoxide ‐SO – -, and changes in their transmission were observed.
The origin and intensity of the SO 3oscillation bands at 1040 cm −1 is a strong indication that the SS disulfide bonds were cleaved and subsequently oxidized to cysteic acid radicals by hydrogen peroxide in the process. preprocessor. It should also be noted that an increase in the protease ratio (at the same pH, i.e., 4) causes further changes to occur, which in turn convert cysteic acid to cysteine monoxide and thus alter bands at 1073 cm −1 and 1075 cm −1 are 6% and 9%, respectively. This indicates that sulfur and sulfur compounds play an important role in the surface treatment of wool fibers, and therefore sulfur-deficient sheep wool may require mild treatment.
Further studies were carried out to evaluate the wool treatment-induced changes in the yarn structure by increasing the pH from 4 to 7. The infrared spectra of the fibers before and after the yarn treatment were studied by using Fourier transform infrared spectroscopy. The results are shown in Figure 4 . It can be seen that by increasing the pH, the transmittance value also increases, which indicates that there may be sulfur depletion and sulfur radicals on the surface of the wool fibers. Both the 1073 cm −1 and 1040 cm −1 band frequencies increased in transmittance, indicating surface attenuation of the fiber.
Nano silver antibacterial performance
The antibacterial property of nano-coated fabrics is related to the interaction between nanoparticles and proteins, especially in the thiol groups (sulfhydryl, –SH). Because this tissue helps proteins get bound to it, similarly, this tissue helps enzymes get bound to it. On adhesions, cell metabolism will be inhibited causing microbial death. Wool fibers have achieved excellent antibacterial activity, as shown in Table 1 .
It can be seen that the fabric sample coated with 6% Pro./AgNPs at pH 7 has less antibacterial activity than the other samples. Although this antibacterial activity was slightly inferior to the antibacterial performance of the other samples at pH 4, it was also very significant.
Nano silver affects the volumetric resistivity of wool fibers
Normally, a fiber with a resistance of 1 × 10 10 Ω cm at RH 65% and 20 °C can be considered antistatic. The specific resistance of synthetic fibers is more than 1 × 10 13 Ω cm, and for wool yarns, it is about 1 × 10 11 Ω cm. The specific test results are shown in Figure 5 .
The volumetric resistivity of the samples treated with 3% protease/silver nanoparticles at pH 4 had the lowest resistance, while the samples treated with 6% protease/silver nanoparticles at high pH 7 had the lowest resistivity. higher yield than other models. This suggests that increasing the pH can lead to low resistivity due to the influence of the wool surface properties affected by high pH. Injury to epidermal cells can expose the fiber’s interior, thereby affecting its properties such as ionic bonding on the fiber. As stated initially, more silver is absorbed at lower pH, so a lower tolerance at lower pH is evident.
Nano silver affects the half-life of wool fibers
The specific static half-life test results are shown in Fig.6
The antistatic properties of the treated samples showed that the electrostatic half-life was short in the samples treated using 3% protease. This is because the rapid dissipation of the accumulated charges is facilitated by more silver nanoparticles. The electrostatic half-life of other samples was also significantly reduced compared with 3% protease suggesting that surface modification by descaling and high pH treatment can affect the antistatic properties of wool. . The effect of flakes on the loading of silver nanoparticles is due to the flake composition which is made up of cysteine which helps to bind the silver nanoparticles on the surface. It can be seen that removing the scale layer reduces the electrostatic half-life of the fabric to a certain extent.
Nano silver affects the interaction voltage of wool fibers
The antistatic treatment of the frictional electrostatic voltage test is shown in Figure 7 .
It can be seen that using 3%, 6% and 9% protease are all effective enough to reduce the friction on the wool surface and even use less protease (i.e. 3%) in combination with the particles. Nano silver can greatly improve the antistatic properties of wool. . At higher pH, the wool’s surface can suffer and its antistatic properties suffer. Electrostatic voltage drops from 7000 V to 1400 V and even as low as 200 V. Incorporating silver nanoparticles and removing residue can give wool yarns good antistatic properties even after washing in soap room twenty times.
Nano silver affects the coefficient of friction
The surface of the wool fibers is usually covered with scales, and these flakes can degrade to varying degrees or degrees by varying the ratio of proteases used in the flaking process. After treatment using a high percentage of protease, the outer layer of the scale is almost completely peeled off and the surface becomes smoother. As a result, the surface of the yarn with less flaking flakes has higher friction but is still much improved compared to the untreated yarn. The test results of the coefficient of friction of wool yarn are shown in Figure 8 .
It can also be noted that removing the scale can achieve a good frictional effect. They are expressed as the value of the difference of the coefficient of friction along the scale direction and/or relative to the scale direction, which is significantly reduced. For that reason, it is better to incorporate silver nanoparticles in the protease treatment of wool fibers at lower protease ratios and at lower pH used. The flaking affects the SS bonds and supergroups on the wool cuticle, which are essential in the loading of silver nanoparticles on wool.
Effective conclusion of nano silver
The SS disulfide bond is oxidized to cysteic acid radicals by hydrogen peroxide, and the increased protease ratio causes further changes to occur, converting cysteic acid to cysteinemonoxide of bands oscillating at 1073 cm −1 and 1075 cm −1 for 6% and 9% proteases all at pH 4. This indicates that sulfur and sulfur compounds play an important role in the surface treatment of wool fibers, and thus Accordingly, wool from sulphur-deficient sheep may require light handling. Volumetric resistivity is affected by pH. A high pH causes an excessively high resistivity, while a low pH has good electrical conductivity; therefore, silver nanoparticles give better results if incorporated at pH 4.
The half-life and voltage were both improved after treatment. The surface of the wool fibers is usually covered with scales, and these flakes can degrade to varying degrees or degrees by varying the ratio of proteases used in the flaking process. After treatment using a high percentage of protease, the outer layer of the scale is almost completely peeled off and the surface becomes smoother. As a result, the surface of the yarn with less flaking flakes has higher friction but is still much improved compared to the untreated yarn. It can also be noted that removing the scale can achieve a good frictional effect. They are expressed as the value of the difference of the coefficient of friction along the scale direction or with respect to the scale direction, significantly reduced. Therefore, incorporation of silver nanoparticles in wool protease treatment is better at lower pH and lower protease utilization rate. The flaking affects the SS bonds and supergroups on the wool cuticle, which are essential in the loading of silver nanoparticles on wool.
Reference source:
Hafeezullah Memon , 1 , 2 Hua Wang, 3 Sohail Yasin , 4 và Adeel Halepoto 5